SOUTHEND - 3 The new beginning

[LN-KGL]

These 63/69 dB noise levels will be measured within each individual home with all windows shut.

The noise reduce with distance. As an example: The maximum noise from an Airbus A320 with CFM56 engines with max possible thrust on brakes is 109 dB measured 60 metres from centre of the aircraft. If you increase this distance to 10 times that which is 600 metres, you will find by measuring the sound level that it's now 89 dB or lower. The reason for me saying "or lower" is that calculation of noise is based on free field/free sight conditions and with hard surface ground. Grass, shrubs, trees, embankments will absorb and/or deflect the noise. The weak point in every house, when it comes to sound proofing, is the windows. A typical single glass windows reduce the noise with around 20 dB, so a house with single glazed windows 600 metres from an A320 om max power without any vegetation around it (free field) would have had a maximum sound level inside the house of 69 dB. Double glazed sound proof windows will typically reduce the sound with 43-46 dB, but then the walls of the house would be the main noise provider to the inside of the house. If that wasn't the case the same house 600 metres from the A320 at full power would have had peak noise level of 46 dB which would had been equal to a refrigerator humming.

So talking about noise levels as absolute figures is nonsense. The use of the noise levels at Luton have no relevance since the three measuring points at LTN is only placed in accordance with Annex 16/FAR Part 36 Takeoff Reference Point (6,500 metres from brake release). Dependent of how much above 88 dB the last aircraft had, all measured noise levels show results below Stage 3 maximum levels for take offs. This does not tell anything about how little/much noise the residents at the far end of Ludlow Avenue experience the noise to be inside their houses. The CFM56 on an A320 is at the noisiest 120° out from the nose (4 and 8 o'clock). If the aircraft is flying directly above the measuring spot it's 3-4 dB lower than if it's showing the side of the aircraft to measuring unit.

In other word you can't say yes or no to if the 63/69dB limits are broken without measuring inside some of the houses in the neighbourhood to an airport.